When mapping is executed multiple times in vim selection mode

Question

function Hello()
        echo "hello world\n"
endfunction

map <leader>w :call Hello()<CR>

In normal mode, I press <leader>w to call the Hello() function once, but if I am in the selection mode, the Hello() function will be called n times, the number of n times and the selection The number of rows is the same. If I now want to call the function only once in selection mode, how should I deal with it?

Answer 1

Processing range by yourself:

function Hello() range

See also:

:help :call